How does deforestation affect the hydrologic cycle?

Deforestation is when forests are cut down.

This is done for a variety of reasons, generally to harvest timber, clear land for livestock grazing, or open up sites for real estate and mineral development.

The effects of deforestation are far-reaching and it’s important to take a look at how reckless harvesting and clearcutting of forests impacts us all.

One way that deforestation harms our societies and our planet is by interrupting and harming the water cycle, or the hydrologic cycle.

How does deforestation affect the hydrologic cycle?

Deforestation affects the hydrologic cycle by interrupting and reducing it. It essentially does this by cutting out one of the crucial components of the hydrologic cycle.

So, what is the hydrologic cycle anyway?

The hydrologic cycle sounds like a complex subject but it’s actually quite simple:

It’s the way water transforms and cycles through the earth’s atmosphere, water bodies, and landmass.

By evaporating, condensing, and falling as rain, water sustains life and the food we eat.

A crucial part of the hydrological cycle is trees, and when there are fewer trees it does enormous damage.

Here’s how.

1) Deforestation causes droughts

First and foremost, cutting down forests causes less rain to fall.

Trees not only recycle carbon and breathe it back out as oxygen; they also absorb water through their foliage and trunks and release what they don’t need as nourishment back into the atmosphere.

No trees, no transpiration of water.

No transpiration of water, no rain.

No rain, no crops. Deserts. Drought. Dead crops, animals, and people.

A single large tree can suck 100 gallons of water a day up through its roots and put that out into the air.

Cut down 1,000 trees and you just reduced rainfall by 100,000 gallons. That’s a lot!

2) Deforestation destabilizes the soil

In addition to their vital role in transpiring water and drawing it out of the ground and recycling it through their leaves, trees have a vital role to play in nourishing the soil.

When you cut down a tree, you also kill its roots.

Roots help to stabilize the ground and nourish it. Once they are gone, the ground dries out and often becomes unstable and unpredictable.

Water begins to pool heavily in some places and weaker soil gives way to landslides, flooding, and mudslides.

Without the stabilizing and distributive role of the roots, water begins to run wild and regions start cycling through times of intense drought and mudslides which alternate unpredictably.

As deforestation picks up the pace and continues even more due to modern technology and global demand for wood and meat, the situation continues to worsen.

Shockingly, an estimated 46% of all forests have been cut down since the start of humankind.

3) Deforestation kills crop production

When water dries up, so do crops.

Cutting down forests is ultimately the same as cutting down fields of wheat, corn, and vegetables.

While the cleared areas may be able to be used for livestock grazing, they become unusable for many crops without moving inexpensive and environmentally destructive irrigation systems.

Plus, these irrigation systems still need to get their water from somewhere!

And eventually, that supply begins running low as more and more of the world’s forests get cut down beyond a sustainable level.

From the Amazon jungle to the Congo Basin to the West Coast of Canada, forest clearcutting is an extremely serious problem.

When you cut down trees in one area of the world, large streams of water vapor in the clouds cease to flow sufficiently, leaving places halfway around the world without water.

It’s an exponential cycle that worsens. Coupled with the current food insecurity due to the war in Ukraine, deforestation poses a dire problem for the future of agriculture.

You need trees if you want to have food.

4) Deforestation leads to water pollution

When there are fewer trees, pollutants and runoff increase.

This means dirtier water that takes more time, money and energy to clean and sick wildlife in the area.

Drinking water and the water table as a whole become filthy and chemicals and pollutants clog the water.

The lack of root systems leads to the rain that does come washing water directly into rivers, lakes, animal drinking areas, and surrounding areas.

The roots act as a kind of filter of the groundwater sediment, and when there aren’t enough of them then it runs off into the surrounding area without having been cleaned.

This not only harms the environment but also leads to fish being full of chemicals and unhealthy ingredients as well.

5) It hikes up water prices for human beings

When you deforest an area and interrupt the hydrologic cycle, you make clean and potable water more difficult and costly to get to human beings.

This increases the price of it in towns and cities and makes it harder and more energy-consuming for municipalities to derive clean water.

Regulations exist in most places for clean drinking water, but getting the standards met becomes more difficult once the water is less plentiful and more polluted.

Large forests have a significant cleaning effect on water and produce cleaner water that’s able to be used more quickly and with less treatment cost.

In New York City, for example, efforts were made to save forests in the Catskill Mountains amounting to over $1 billion. This saved a 1 million acre area of forest and saved the city $8 billion they would have had to spend building a treatment plant.

This is a great example of how short-term greed and gain from deforestation end up costing much more to governments and taxpayers than long-term thinking that takes into account forest health.

6) Deforestation decreases rainfall

Trees help distribute water around the world.

When there are fewer of them, there is less condensation in the clouds and, subsequently, less rain.

When you cut down forests on one side of the world, you can be robbing the other side of the world of enough rain to grow its crops.

This is how deforestation becomes an increasingly global concern, rather than just a national one.

The cessation of rainfall in one area is often directly linked to the clearcutting of large areas whose rainclouds are accustomed to migrate to the other area.

A prime example would be how clear-cutting going on now in central Africa is vastly decreasing rainfall per year in the US Midwest.

Texas is also having more and more droughts due to the Amazon being clear-cut and losing an average of 18 trees per second last year in 2021.

7) Deforestation makes the fire risk much worse

When you cut down a lot of trees, the resulting decreased rainfall, soil erosion, and desertification vastly increase the risk of forest fires.

What makes it worse in places like Brazil’s massive Amazon rainforest, is that fires are often started on purpose to burn off shrubbery and leftover small tries to ready the land more rapidly for grazing or development.

The result, all too often, is huge forest fires that pump pollution and carbon into the atmosphere and make people sick and land uninhabitable for years to come.

Fertile soil becomes charred and sterile, people suffer from respiratory illness and many other problems as the smoke settles.

From Chiang Mai to Rondonia, Brazil, the problem of slash and burn agriculture and deforestation is incredibly huge.

What’s worse is that many developing nations and places like Brazil, Thailand, and Indonesia don’t look like they have the political will to do something about it.

8) Deforestation is one of many problems impacting the hydrologic cycle

Deforestation is not the only man-made danger threatening the hydrologic cycle.

Many man-made activities are also cutting into nature’s rhythm, including the building of massive dams to produce hydroelectricity, mass irrigation and overuse of water, climate change, and fossil fuel consumption on a vast scale.

All these activities and more point to a growing problem that is impacting the hydrologic cycle and many of its associated benefits.

The hydrologic cycle is crucial to the world to keep turning and for us to keep having seasons, growing crops, and healthy bodies and minds fed by clear springs of clean water.

Turning deforestation to reforestation

Reforestation efforts are widespread in various countries, especially places like Canada where government funding is directly going toward reforestation.

Still, trees take many decades to grow, and slapping a bandaid on the problem isn’t going to solve it.

The truth is that concerted action is needed as soon as possible in order to start turning this around.

Global attempts to curb climate change have proven ineffective, and the outlook for regulating deforestation more effectively looks similarly difficult.

Enormous pressure must be put on governments and corporations, along with alternative ways of living and producing such as permaculture and sustainable farming cooperatives.

If deforestation continues unabated on its current trajectory, the outlook is truly bleak:

A world beset by food insecurity, desertification, wars, and fights over water and resources is looming around the corner.

Concerned citizens need to partner with lawmakers and advocacy groups to begin demanding industrial and corporate change on a large scale.

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Paul Brian

Paul R. Brian is a freelance journalist and writer who has reported from around the world, focusing on religion, culture and geopolitics. Follow him on and visit his website at

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